## 20111011

### Astronomy midterm question: Jupiter as evening star?

Astronomy 210 Midterm 1, fall semester 2011
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board(*) was asked and answered:
Darjeeling Snow: Very often at night there is an evening star [above the west horizon just after sunset]. Is it Jupiter...?
lipi: [J]upiter impossible...
Discuss whether this answer is correct or incorrect, and how you know this. Support your answer using a diagram showing the positions of the sun, Jupiter, Earth, and an observer on Earth.

• p = 20/20:
Correct. Diagram with Earth (inner heliocentric orbit) and Jupiter (outer heliocentric orbit); Jupiter can be seen above the west horizon at sunset.
• r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discusses how it is possible, but diagram shows Jupiter above the east horizon at sunset, or above the west horizon at sunrise.
• t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Heliocentric diagram has Jupiter above east horizon at sunrise, or geocentric diagram with Jupiter above west horizon at sunset.
• v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Diagram and discussion problematic.
• x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Problematic discussion with no diagram.
• y = 2/20:
Irrelevant discussion/effectively blank.
• z = 0/20:
Blank.
Section 70158
Exam code: midterm01sg5U
p: 4 students
r: 13 students
t: 9 students
v: 5 students
x: 6 students
y: 0 students
z: 0 students

A sample "p" response (from student 7272) with Jupiter very low above the west horizon at sunset: